package com.bdqn.service;

import com.bdqn.pojo.User;
import com.bdqn.repository.UserRepository;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * UserServiceImpl
 *
 * @author LILIBO
 * @since 2022-01-16
 */
@Service
public class UserServiceImpl implements UserService {

    @Resource
    private UserRepository userRepository;

    /**
     * 实现动态查询
     *
     * @param param
     * @param pageable
     * @return
     */
    @Override
    public Page<User> findPageByMap(Map param, Pageable pageable) {

        return userRepository.findAll(new Specification<User>() {
            @Override
            public Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>();
                if (param.get("usrName") != null) { // 动态 SQL
                    predicates.add(cb.like(root.get("usrName"), "%" + param.get("usrName") + "%"));
                }
                if (param.get("roleId") != null) {
                    predicates.add(cb.equal(root.get("usrRoleId"), param.get("roleId")));
                }
                return cb.and(predicates.toArray(new Predicate[predicates.size()]));
            }
        }, pageable);

        // MySpecification mySpecification = new MySpecification(param);
        // return userRepository.findAll(mySpecification, pageable);
    }
}
